This is a WHERIGO cache. To find it, you need to download the accompanying Wherigo Cartridge to a compatible device and play it. Successfully completed, the cartridge will lead you to the cache location. GPS receivers that can play the Wherigo carts include the Garmin Colorado, the Garmin Oregon, the Garmin Nuvi 500/550 or a GPS-enabled PocketPC. If you are using a GPS-enabled PocketPC you will need the Wherigo player.
Additionally, Wherigo can also be played on an iPhone, iPad, or iPod Touch using the Wherigo app or on an Android phone with the WhereYouGo app. A player is being developed for the Window Phone, but is open for beta testing by invite only, I believe. See this thread on the GC forums.
At the given location, you will find a bridge. On the east side of the bridge you'll find a Fox, a Chicken, and some Grain. Your chore is to transport all three across to the west side of the bridge. However, you can only carry one item at a time. Leave the fox alone with the chicken, unsupervised, and the fox will eat the chicken and you will lose. Likewise, leave the chicken alone with the grain, and the chicken will eat the grain and you will lose. Fortunately for you, "losing" just means that you have to quit the cartridge and start the game over again. Best of luck!
Congratulations to no muggle for being FTF!
This cartridge has been field tested on the iPhone 5 (iOS 7.0) using the Wherigo app, and on a Nuvi 550 using the built-in Wherigo player. In general, Wherigo carts tend to run better on smart phones than on Garmin devices. For example, the function that leaves a completion code in your inventory at the end of the game doesn't seem to work on the Nuvi 550. Let me know of your experiences on other devices.